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Thursday, March 10, 2011 — A fad diet that involves daily dosing of a pregnancy hormone is experiencing a "rebirth" with a big push from one of America's most popular television doctors, Mehmet Oz, MD.

Last month, Oz devoted an entire show to claimed benefit of the human chorionic gonadotropin (hCG) diet. A highlight of the Oz show — an audience packed with believers who offered testimonials about the sure fire combination of a daily injection of the hormone and 500 calorie a day diet.

His bottom line: Though studies from the past have found that hCG is no better than a placebo, he sees "a lot of reasons — intriguing reasons — to re-evaluate the diet.

"By researching hCG — and this is something I'm excited about — I think we might find new ways to help millions of people who do not have another solution, find an option," he said. "And for that reason, I think it's worth investigating."

Skeptics point out that a 500 calorie diet would alone cause a drop in pounds, and Oz does not recommend that severely restricted regimen. He advocates 1,200 calories instead.

Moreover, Oz said the diet should only be undertaken under the supervision of a doctor, who would prescribe hCG for injection. He warned that over-the-counter oral supplements do not work.

Yet a handful of specialists contacted by MedPage Today and ABC News questioned the ethics of colleagues who endorse — even market — the hCG diet, which costs anywhere between $800 and $1,150 for a consultation that includes blood work, assessment of body metrics, and an initial prescription.

"I think it is sad that there are quality devices and pharmaceuticals that have data that prove weight loss that cannot be sold, but that marketers who pose as doctors can profit from selling something that has no proven benefit," said Mitchell Roslin, MD, of Lenox Hill Hospital in Manhattan.

"It is not surprising that Mehmet has taken this position," Roslin added. "Mehmet is a wonderful cardiac surgeon, excellent athlete, and a phenomenal self-promoter."

Carla Wolper, EdD, RD, of the obesity research center at St. Luke's and Roosevelt Hospitals in Manhattan, said Oz used bad judgement when he had as a guest a doctor who promotes the treatment — Sheri Emma, MD, a New Jersey physician.

"Allowing her to go unchallenged is more evidence that Oz is no longer legitimately interested in the truth, but in notoriety, money, and keeping his program on the air," Wolper said.

However, some clinicians agreed with Oz that further study may be warranted, given that many of the studies were done years ago and more modern injections may yield different results.

"I would agree that research needs to be updated," said Lona Sandon, MEd, RD, of the University of Texas Southwestern Medical Center and spokesperson for the American Dietetic Association, which does not endorse the hCG diet.

"Just because something is allowed for off-label use does not mean it is safe or effective," she said. "People are spending thousands of dollars on this with little guarantee of safety and efficacy."

But David Katz, MD, of Yale University, who wrote a Huffington Post article critical of the hCG diet in January, said it would be "a waste of research funding to re-discredit a scam every time it gets reintroduced."

"The treatment doesn't make any sense," he said. "Who associates pregnancy with either weight loss or fat loss, or appetite suppression? And the studies have been negative. What is the basis to reintroduce it?"

British physician Albert Simeons first championed the diet in the 1950s. Since then, more than a dozen trials have refuted its efficacy, including several randomized, placebo-controlled trials that found hCG no better than a saline injection.

As a guest on the episode of the Dr. Oz Show devoted to the hCG diet, Pieter Cohen, MD, of Harvard Medical School, said the heart of the debate lies in whether the shot simply generates a placebo effect.

That's a possibility given that no one is quite sure of the mechanism by which hCG may work since pregnancy is not usually associated with a decrease in hunger.

Albert Levy, MD, of Mount Sinai Medical School in New York City, said reducing caloric intake to 500 calories per day could induce a ketotic state, "which will induce a lack of appetite and consequently more weight loss."

"Let's not forget the bad consequences of a ketotic state, particularly in diabetic patients," Levy added.

Although hCG injections are FDA-approved for treating female infertility (as well as certain male conditions including undescended testes and hypogonadism secondary to a pituitary deficiency), the agency maintains the stand it took on the diet years ago:

"Since the mid-1970s, FDA has required labeling of hCG to state that [it] has not been demonstrated to be effective adjunctive therapy in the treatment of obesity. Numerous clinical trials have shown hCG to be ineffectual in producing weight loss," the agency said in a statement.

FDA also warns of a host of potential side effects, including an increased risk of blood clots, headaches, irritability, fatigue, restlessness, depression, swelling, breast tenderness or enlargement, and water retention.

The drug can also cause potentially life-threatening ovarian hyperstimulation, a syndrome of sudden ovarian enlargement.

Whether the hCG diet will be re-evaluated remains to be seen, but many researchers are confident the hype will eventually recede.

"The resurgence of the hCG diet only goes to show that fads, much as their name states, come and go on a regular basis," said Connie Diekman, RD, MEd, director of university nutrition at Washington University in St. Louis. "It is more important that people lose weight with an eating and activity plan that ensures they can keep the weight off."